Tsarin aikin Semiconductor

Za ka iya fahimtarsa ​​ko da ba ka taɓa yin nazarin kimiyyar lissafi ko lissafi ba, amma yana da ɗan sauƙi kuma ya dace da masu farawa. Idan kana son ƙarin sani game da CMOS, dole ne ka karanta abubuwan da ke cikin wannan batu, domin sai bayan fahimtar tsarin aiwatarwa (wato, tsarin samar da diode) za ka iya ci gaba da fahimtar abubuwan da ke gaba. Sannan bari mu koyi game da yadda ake samar da wannan CMOS a cikin kamfanin kafa a cikin wannan batu (idan aka ɗauki tsarin da ba na ci gaba ba a matsayin misali, CMOS na tsarin ci gaba ya bambanta a tsari da ka'idar samarwa).

Da farko dai, dole ne ka san cewa wafers ɗin da masana'antar ke samu daga mai samar da kayayyaki (wafer ɗin siliconmasu samar da kayayyaki) ɗaya bayan ɗaya ne, tare da radius na 200mm (inci 8masana'anta) ko 300mm (Inci 12masana'anta). Kamar yadda aka nuna a cikin hoton da ke ƙasa, a zahiri yana kama da babban kek, wanda muke kira substrate.

Duk da haka, bai dace mu kalli hakan ta wannan hanyar ba. Muna kallon daga ƙasa zuwa sama mu kalli kallon giciye, wanda ya zama hoton da ke ƙasa.

Na gaba, bari mu ga yadda samfurin CMOS ya bayyana. Tunda ainihin tsarin yana buƙatar dubban matakai, zan yi magana game da manyan matakan wafer mai inci 8 mafi sauƙi a nan.

 

 

Yin Rijiya da Juyawa Layer:

Wato, ana dasa rijiyar a cikin substrate ta hanyar dasa ion (Ion Implantation, wanda daga baya ake kira imp). Idan kuna son yin NMOS, kuna buƙatar dasa rijiyoyin P-type. Idan kuna son yin PMOS, kuna buƙatar dasa rijiyoyin N-type. Don saukaka muku, bari mu ɗauki NMOS a matsayin misali. Injin dasa ion yana dasa abubuwan P-type da za a dasa a cikin substrate zuwa wani takamaiman zurfin, sannan yana dumama su a babban zafin jiki a cikin bututun tanderu don kunna waɗannan ions da kuma yaɗa su a kusa. Wannan yana kammala samar da rijiyar. Wannan shine yadda yake bayan an kammala samarwa.

Bayan yin rijiyar, akwai wasu matakan dasa ion, manufarsu ita ce a sarrafa girman wutar lantarki ta tashar da ƙarfin wutar lantarki. Kowa zai iya kiranta da inversion layer. Idan kuna son yin NMOS, ana dasa inversion layer da P-type ions, kuma idan kuna son yin PMOS, ana dasa inversion layer da N-type ions. Bayan dasawa, shine samfurin da ke ƙasa.

Akwai abubuwa da yawa a nan, kamar makamashi, kusurwa, yawan ion yayin dasa ion, da sauransu, waɗanda ba a haɗa su cikin wannan batu ba, kuma ina ganin idan kun san waɗannan abubuwan, dole ne ku zama mai bincike a ciki, kuma dole ne ku sami hanyar koyo game da su.

 

Yin SiO2:

Za a samar da silicon dioxide (SiO2, wanda daga baya ake kira oxide) daga baya. A cikin tsarin samar da CMOS, akwai hanyoyi da yawa na yin oxide. A nan, ana amfani da SiO2 a ƙarƙashin ƙofar, kuma kaurinsa yana shafar girman ƙarfin wutar lantarki da girman wutar lantarki ta tashar. Saboda haka, yawancin masana'antun suna zaɓar hanyar iskar shaka ta bututun tanderu tare da mafi kyawun inganci, mafi daidaitaccen sarrafa kauri, da mafi kyawun daidaito a wannan matakin. A zahiri, yana da sauƙi sosai, wato, a cikin bututun tanderu mai iskar oxygen, ana amfani da zafin jiki mai yawa don ba da damar oxygen da silicon su amsa sinadarai don samar da SiO2. Ta wannan hanyar, ana samar da siririn Layer na SiO2 a saman Si, kamar yadda aka nuna a cikin hoton da ke ƙasa.

Tabbas, akwai kuma bayanai da yawa na musamman a nan, kamar adadin digiri da ake buƙata, yawan iskar oxygen da ake buƙata, tsawon lokacin da ake buƙatar yawan zafin jiki, da sauransu. Waɗannan ba su ne abin da muke la'akari da shi yanzu ba, waɗannan sun yi takamaiman bayani.

Tsarin ƙarshen ƙofar Poly:

Amma bai ƙare ba tukuna. SiO2 daidai yake da zare, kuma ainihin ƙofar (Poly) ba ta fara ba tukuna. Don haka matakinmu na gaba shine sanya layin polysilicon akan SiO2 (polysilicon shima ya ƙunshi sinadarin silicon guda ɗaya, amma tsarin lattice ya bambanta. Kada ku tambaye ni dalilin da yasa substrate ɗin ke amfani da silicon crystal guda ɗaya kuma ƙofar tana amfani da polysilicon. Akwai littafi mai suna Semiconductor Physics. Kuna iya koyo game da shi. Abin kunya ne~). Poly kuma mahaɗi ne mai matuƙar mahimmanci a cikin CMOS, amma ɓangaren poly shine Si, kuma ba za a iya samar da shi ta hanyar amsawa kai tsaye tare da substrate Si kamar girma SiO2 ba. Wannan yana buƙatar CVD mai ban mamaki (Chemical Vapor Deposition), wanda shine don amsawa ta hanyar sinadarai a cikin injin kuma ya zuga abin da aka samar akan wafer. A cikin wannan misalin, abin da aka samar shine polysilicon, sannan a zuga shi akan wafer (a nan dole ne in ce poly ana samar da shi a cikin bututun tanderu ta hanyar CVD, don haka samar da poly ba a yin shi ta hanyar injin CVD mai tsabta).

Amma polysilicon da aka samar ta wannan hanyar za ta yi karo a kan dukkan wafer ɗin, kuma yana kama da haka bayan ruwan sama.

 

Bayyanar Poly da SiO2:

A wannan matakin, an samar da tsarin tsaye da muke so, tare da poly a saman, SiO2 a ƙasa, da kuma substrate a ƙasa. Amma yanzu duk wafer ɗin kamar haka ne, kuma muna buƙatar takamaiman matsayi ne kawai don zama tsarin "famfo". Don haka akwai mafi mahimmancin mataki a cikin dukkan tsarin - fallasa.
Da farko mun shimfiɗa wani Layer na photoresist a saman wafer ɗin, kuma ya zama kamar haka.

Sai a saka abin rufe fuska da aka ayyana (an ayyana tsarin da'irar a kan abin rufe fuska), sannan a ƙarshe a haskaka shi da haske mai tsawon tsayi. Mai hana haske zai kunna a yankin da aka haskaka. Tunda yankin da abin rufe fuska ya toshe ba a haskaka shi da tushen haske ba, wannan ɓangaren mai hana haske ba a kunna shi ba.

Tunda na'urar daukar hoton da aka kunna tana da sauƙin wankewa ta wani takamaiman ruwan sinadarai, yayin da na'urar daukar hoton da ba a kunna ba ba za a iya wanke ta ba, bayan an yi amfani da hasken rana, ana amfani da wani takamaiman ruwa don wanke na'urar daukar hoton da aka kunna, kuma a ƙarshe ya zama kamar haka, yana barin na'urar daukar hoton inda Poly da SiO2 ke buƙatar a riƙe su, sannan a cire na'urar daukar hoton inda ba sai an riƙe su ba.